For example, in fabricating steps of a semiconductor device, when a foreign matter or a pattern defect of short circuit, disconnection or the like (hereinafter, these are generally described as defects) is present on a semiconductor substrate (wafer), the defect causes a failure of insulation failure, short circuit or the like of wirings. Also, in accordance with miniaturization of a circuit pattern formed on a wafer, a minute defect causes insulation failure of a capacitor or breakage of a gate oxide film or the like. These defects are mixed in various states by various causes such as those that occur from a movable portion of a carrier device, those generated from the human body, those generated by a reaction at an inner portion of a processing device by a process gas, and those mixed into a drug or a material or the like. Therefore, it is important for mass-producing a semiconductor device to detect a defect generated in fabrication steps, swiftly find a source of generating the defect, and stop creating a failure.
Up to now, as a method of pursuing a cause of generating a defect, there has been a method of first, specifying a defect position by a defect inspecting device, observing in details and classifying the defect by a review device of a scanning electron microscope (SEM) or the like, comparing inspection results acquired at respective steps of fabrication with preserved database to thereby estimate a cause of generating a defect.
Here, the defect inspecting device is an optical defect inspecting device of irradiating a surface of a semiconductor substrate with a laser, subjecting scattered light from the defect to a dark field observation to thereby specify a position of a defect, or an optical outlook inspecting device or an SEM type inspecting device of defecting a bright visual field optical image of a semiconductor substrate by irradiating a semiconductor substrate with a lamp or a laser, or an electron beam, and comparing the bright visual field optical image with reference information to thereby specify a position of a defect on a semiconductor substrate. Such observation methods are disclosed in Patent Literature 1 or Patent Literature 2.
Also, concerning a device of observing in details a defect by SEM, Patent Literature 3 describes a method and a device of detecting a position of a defect on a sample by an optical microscope mounted to an SEM type defect observing device by using position information of the defect on the sample detected by other inspecting device, modifying the position information of the defect acquired by detecting by the other inspecting device, and thereafter, observing (reviewing) in details the defect by the SEM type defect observing device.
Further, Patent Literature 4 describes high sensitivity formation of a dark visual field type optical microscope by arranging a spatially distributed filter on a pupil surface of a detecting optical system or vicinity thereof.